Many mechanical systems, such as those found in the automotive field for instance, are integrated into operating environments that realize high temperatures, pressures and the presence of fluids, each of which often is proximate to an electrical assembly. Monitoring the conditions of various aspects of systems in these types of applications using electronics presents challenges for designers and system providers, in part, as the viability of these components and their associated connectivity in such environments may be inadvertently compromised. Similarly, despite such environments, there exists a need to measure and convert certain physical characteristics into electrical signals for monitoring and control purposes. In some cases, the need to convert certain physical phenomena into electrical signals requires the electronics (i.e., sensor assembly) to be immersed or submerged in fluids of the environment.
For instance, in the automotive environment, there is a need to provide pressure sensors to determine various hydraulic transmission fluid (hereafter referred to as ATF) pressures during operation of an automatic, automated manual, dual clutch, or other electronically controlled transmission. To determine such data characteristics regarding pressure of the ATF for the operation, a pressure sensing device is often submerged in the ATF. (In some designs, the fluid measured is separate from the ATF in the sump.) These pressure sensing devices provide the determined pressure data as electrical signals (i.e. digital data) to receiving devices while the pressure sensing devices are actively submerged in the transmission sump. While in the transmission sump, these pressure sensing devices are often subjected to both extremes of high and low temperatures of the ATF, as well as the chemical lubricating and penetrating properties of the engineered fluids present (i.e., operating fluids). The submerging of a pressure sensor in the ATF causes these types of sensing devices, and more specifically the electronics and connectivity of such sensors, to become prematurely damaged, particularly over time. Therefore, it is highly desired that the internal workings (i.e. electronics and electrical connectivity) of the sensors be protected from the environment and more specifically from fluid penetration to ensure the operational reliability of these critical sensors as designed. This desire however, presents challenges beyond basic sealing of the sensor as fully sealed sensors often still require electrically electrical connectivity with the electronic components within the sensor to an external power source as well as electrical communication signal lines to pass information to other components.
For instance, it is generally known that a common method of sealing is to first employ a connector body that uses plastic over molded materials such as polybutylene terephthalate (PBT) or polyphenylene sulfide (PPS) to rigidly locate one or more metallic connector pins; and then seal the connector body to the remaining sensor structure containing the necessary sensing element and electronics using one or more elastomeric O-rings. Although this technique is plausible, it is not useful for the present exemplary situation and is further limited in its applications.
In some situations, there have been attempts to build on the basic limited approach by employing additional elastomeric O-rings, to seal the connector body to its mating electrical connector, and/or to further use a secondary sealing process such as vacuum impregnation of the voids between the metallic pins and over molded plastic or epoxy potting, to prevent fluid penetration along the pins. However, significant resources, costs and time are expended on plastic, epoxy, and elastomeric materials development and selection choices to meet the sealing requirements at the extremes of temperature experienced in the automotive industry, for example, making this approach overly complex, limited in its application and deficient in efficiencies.
Accordingly, what is desired is a cost-effective solution for providing reliable and accurate pressure data measurements from pressure sensing devices submerged in operating fluids while satisfying requirements for fluid resistance and electrical connection integrity of the submerged components.
As used herein the terms device, apparatus, system, etc. are intended to be inclusive, interchangeable, and/or synonymous with one another and other similar arrangements and equipment for purposes of the present invention though one will recognize that functionally each may have unique characteristics, functions and/or operations which may be specific to its individual capabilities and/or deployment.